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本文结合广(州)惠(州)高速公路小金口双连拱隧道实际工程,利用相似模型在Ⅱ、Ⅲ类围岩条件下,采用三导坑法、双导坑法和中导坑拓展法三种施工方法进行模型试验研究。得出最大的周边径向位移发生于拱顶, 其次为拱腰部位,径向位移收敛警戒值的范围不能超过10mm;从洞室的失稳特征分析,衬砌最容易在隧道边墙及中墙与衬砌搭接处出现裂缝;通过模型试验提出了连拱隧道在Ⅲ类围岩中采用中导坑拓展法施工,对围岩扰动较小,有利于隧道稳定。研究成果对双连拱隧道的设计与施工具有重要指导作用。
Based on the actual project of the Xiaoguankou double-arch tunnel on the Guang-Hui Expressway, this paper uses the similar model to the surrounding rock conditions of type II and III. The three-pilot pit method, the double pilot pit method and the mid-pit excavation method Three kinds of construction methods for model test research. It is concluded that the maximum radial displacement occurs in the vault, followed by the arch waist, and the range of the radial displacement convergence warning value can not exceed 10mm. From the analysis of the instability of the tunnel, And the cracks appeared at the lap joint. Through the model test, it is proposed that the multi-arch tunnel is constructed by using the mid-guide way in the surrounding rock of type III, which has less disturbance to the surrounding rock and is favorable to the stability of the tunnel. The research results have an important guiding role in the design and construction of double-arch tunnels.